*{
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

.bg{
    width: 100vw;
    height: 100vh;
    background-image: linear-gradient(#Fddaff,#E2B0FC,#BAC3FB,#AAE1F4,#B3FBED);
    display: flex;
    justify-content: center;
    align-items: center;
}
.content{
    width: 400px;
    min-height: 300px;
    background: #fff;
}

.box{
    border: 1px solid red;
    padding: 20px;
}